1. Field of the Invention
The present invention relates to the technical field of mobile communication, more specifically, to a method and system for multi-mode signal transmission.
2. Description of the Related Art
There are various communication systems in the field of mobile communication currently. The TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) and the GSM (Global System For Mobile Communications) are considered as two of the most common communication system. The said GSM which belongs to the second generation of mobile communication technology (2G) predates the emergence of TD-SCDMA, and correspondingly, the TD-SCDMA belongs to the third generation of mobile communication technology (3G).
The foresaid TD-SCDMA and GSM are not the only solution for the current mobile communication technology. HSPA (High Speed Packet Access), HSPA+(HSPA Evolution) and WCDMA (Wideband Code Division Multiple Access) which are derived from TD-SCDMA and the EDGE (Enhanced Data Rate for GSM Evolution), GPRS (General Packet Radio Service) derived from GSM belong to the communication technology as well. And the mobile terminal users would get improved service with the possible emerging technologies such as 4G network and 5G network in the future.
However, diverse communication technology with variety of communication models is required for a few mobile terminal users simultaneously. In order to achieve such a goal, several power amplifiers should be installed in a limited space based on the current technology condition, as a result, the design difficulty of the integrated PCB board is increased, and so are the manufacturing cost and the circuit fabrication requirements.
Chinese patent No. CN101227212A has disclosed a gain compensation system of a single antenna TD-SCDMA transmitting chain circuit, wherein the system adds a feedback channel from power amplifier PA to a simulating down converter on the basis of the traditional TD-SCDMA transmission system, the system feeds back transmitting signals to a baseband through utilizing the transmitting-receiving chain circuit according to the characteristic that the upper and lower chain circuits are not working simultaneously in a TD-SCDMA communication mode; and the system also comprises an automatic gain control module which is arranged in a baseband processing unit. The foresaid technical solution is only suitable for the single transmitting module, which can not solve the existed problems.
Chinese patent No. CN1475043A has disclosed a nonlinear distortion compensating power amplifier which is provided with a signal transmitting circuit, a gain adjustment circuit, a control circuit, a circuit for measuring the input/output power, and a power amplifier. The foresaid technical solution aims to perform nonlinear compensation to the linear power amplifier, which doses not relate to the coexistence issue between the multiple transmitting modules.